(Iowa News Service) – Advocates for a fair, sustainable and healthy food system have released a report showing that nearly all of the corn seed in Iowa is controlled by just four companies. Economists say concentrations that large can lead to market manipulation. Farm Action’s report shows nearly 90-percent of the corn seed in Iowa is controlled by Corteva and Bayer. AgReliant and Syngenta control the rest. Farm Action President Angela Huffman says that kind of control and concentration is happening all the way from seeds to the consumer’s plate, and she warns it makes market conditions ripe for abuse.

The same type of consolidation is happening in ag operations where livestock are raised in large confinements, and manure runoff is known to damage the air, ground and surface water in rural Iowa.

SALO, FINLAND – AUGUST 22, 2015: Line up of four John Deere agricultural tractors, 6115R and 7340 on the left, at Puontin Peltopaivat Agricultural Harvesting and Cultivating Show.

Operators have said they’re always looking for more efficient and environmentally friendly ways to raise livestock.

Huffman argues that monopolies like this can lead to collusion, price fixing and other types of market manipulation. She and other advocates have called on lawmakers in Congress to address the issue in the pending Farm Bill.

The current Farm Bill, which was supposed to expire in September of last year, has been extended – but debate still hasn’t started on a new version.